Simply Einstein: Relativity Demystified Reprint Edition

Simply Einstein is the best layman's (people such as me) guide to relativity that I have come across in my attempts to gain some understanding of the subject. I have been a science fiction fan since the early Star Trek days and assumed inter-stellar travel's certainty sometime in the near future. I was quite disappointed when a college friend became the bearer of bad news and told me that faster than light travel is impossible. Nearly as disappointing, as I learned more through the years, is the enormous difficulty of getting anywhere near the speed of light. Since then I have been instantly attracted to any article that discusses ways of getting around relativity. Needless to say Einstein's theories have held a fascination for me despite my educational background lacking even a high school physics course and no math past second year algebra. I have enjoyed numerous PBS specials, which touched on the subject as well as books such as The Idiots Guide to Understanding Einstein and E=MC2. Both are excellent and deserve high reviews. My attempts to understand relativity has been an occasional intellectual exercise for me in the same way that others enjoy puzzles, but the success of my efforts has been limited and elusive as touching a cloud.

I purchased Simply Einstein at an Einstein exhibit that has been touring the country. Don't miss it if it comes to your area! Many of the exhibits seemed to be inspired by this book. The author in over approximately 300 pages builds the case for relativity with the aid of a series of analogies and diagrams. He also periodically sums up the main points needed to understand in a clear and concise manner and repeats himself many times to make it sink in and remind the reader. This eliminates the problem of many similar books in which the critical points are stated once or are in a forest difficult to see because of the trees. Understanding the material in Simply Einstein is not a breeze, but if the reader is willing to put in the time and carefully study the examples, a higher level of understanding will be the reward. I am a long way from true understanding, but the level of mystery has been significantly reduced. The success of this book to me is demonstrated by my having reread it twice since buying it a couple of months ago. Perhaps the most satisfying part is at the end when the author remarks that due to the limitations of the human mind, relativity is something he cannot fully understand and doubts Einstein did either.

I have read most of the general treatments of relativity theory, including those by Einstein himself and Nobel Prize Winners Max Born and Richard Feynman as well as books by Martin Gardner and Lillian Lieber and this is far and away the best introduction (with Gardner's book a very close second). Professor Wolfson clearly lays out the basic principles of both the special and general theories of relativity (although most of the book is devoted to the special theory). He begins the book by providing a basic background in the ideas of Galileo, Newton and Maxwell; using these to describe the basics of frames of reference, planetary motion and the ether theory. He then describes the Michelson-Morley experiment and why their null result shows that the ether theory was incorrect. Then he uses this background to develop the basic idea of relativity, namely that "The laws of physics are the same in all uniformly moving reference frames.". This approach is different from that used by others (including Einstein and Gardner) who start from the problem of what is a simultaneous measurement. I found Wolfson's approach to be clearer and easier to follow, but it still requires that the reader closely follow the chain of thought developed by the author. This is not a book to casually read without thinking, but if you put in the effort you should be richly rewarded.

This book studiously avoids any math. In fact, in addition to stating E=Mc^2 and one or two other equations (which are just stated) there is no math in the text. (There is, however, a two-page appendix that derives the time dilation formula of special relativity using only the Pythagorean theorem and high school algebra, but this can be skipped if desired.) The decision to present relativity without any math means that there is no discussion of the transformation of coordinates when two systems are moving at a constant velocity relative to one another, and this means that the book does not discuss why such a transformation works for mechanics but not electromagnetic waves and why the Lorentz transformation must be used for the latter (and the fact that it also works for the former making it the correct overall approach). I do not feel that this is a serious deficiency, as it eliminates an approach that I feel is not absolutely necessary for an elementary presentation. Instead, there is a very clear presentation of the behavior of systems that are moving relative to one another at a constant velocity. The idea of time dilation is clearly presented and is illustrated by many different examples. Even though I was very familiar with the ideas that were presented, I learned a lot and a lot of questions that I had were answered.

General Relativity is discussed in terms of the idea of free fall, which is very clearly explained, as is the idea that a system in free fall is equivalent to one moving at a constant relative velocity. I now more clearly understand the idea of what free fall actually is and why a satellite, such as the space station, does not fall to earth under the action of the earth's "gravity". The word gravity is in quotes because book clearly shows that there is no such thing as "gravity", but that what we call gravity is just the result of the curvature of space. The book ends with a discussion of black holes and how Einstein's General Theory of Relativity has changed our view of time, space and the cosmos.

I would like to comment on two things brought up by other reviewers. One disliked the quality of the paper used in this paperback. Rest assured, there is nothing abnormal about the paper that has been used. It is coarse and non-glossy, but it is exactly the same sort that is used in many other paperback books. In fact, I rather like the use of non-glossy paper because I find that there is less light reflection from it, making the text easier to read. Another reviewer felt that the book was difficult to understand. Relativity is a non-intuitive concept and it requires concentration and a willingness to think very heard about the material that is being presented. You will have to work and concentrate to get the most from this book, but in my opinion this book is the clearest presentation that you are likely to find. Unfortunately, this does not guarantee that you will understand or accept everything that is being presented.

I really enjoyed this book and highly recommend it to anyone interested in relativity. I liked the way the material was organized, the inclusion of background material and the constant restatement of the basic idea of relativity. As mentioned, I liked the discussion of free fall, the principle of equivalence and how these tie together the special and general theories. This book is very suitable for those with a limited mathematics and physics background. I think that book really "demystifies" relativity. It is a great place to start if one is interested in this subject. After reading this book, I would recommend that one then read Gardner's book ("Relativity Simply Explained")as it provides a more conventional approach and then Einstein's book ("Relativity, The Special and General Theory")as it provides the math required for the special theory. As a follow on to these books, I would recommend Feynman's "Six Not So Easy Pieces" as it provides a little more math and a superb analysis of the Michelson-Morley experiment and a derivation of the Lorentz equations. Finally, if one is desirous of learning more about the mathematical basic of the general theory I would recommend Lieber's book ("The Einstein Theory of Relativity"), but be warned you will be exposed to tensor calculus if you do.